The base of an ammunition cartridge case commonly has a “headstamp,” which comprises recessed lettering or other recessed indicia showing who manufactured the case. The headstamp may also indicate the caliber and year of manufacture. As is well known, the base typically also has a primer pocket. The headstamp, primer pocket, or both can be formed in the base using a hardened metal plug called a “bunter.”
The bunter has raised lettering around its face. Thus, when the face of the bunter is pressed against the base of the case, the raised lettering on the bunter forms corresponding recessed letters in the base.
The raised letters on bunters have been formed on the bunter's face by EDM or engraving. Unfortunately, both of these techniques leave the bunter's face with considerable surface roughness, and this roughness is transferred to the cartridge case when the bunter is used to stamp the headstamp on the case. Moreover, the EDM and engraving techniques require a substantial amount of time. Further, when using EDM or engraving, the bunter is not workhardened during the forming process.
It would be desirable to provide a fast, efficient process for forming raised indicia on the face of a bunter. It would be particularly desirable to provide a process that leaves the face of the bunter with a smooth, workhardened surface. It would also be desirable to provide a bunter blank configuration that facilitates such a process.